Probably the most visible effect is on Whanganui's roads where some motorists, who have been used to taking only a few minutes to drive around town, are finding themselves in queues of traffic and frustrated by roading changes and traffic lights.
While it's nothing compared with the traffic challenges bigger cities are facing, it's bad enough for the Whanganui District Council to be receiving a constant stream of complaints, particularly about traffic signals.
We spoke to the council's senior roading engineer Brent Holmes to find out what his team is doing to address the complaints and the council's plans for dealing with the increase in traffic.
Holmes says there has been "a significant traffic growth spike" in the inner city, particularly in the past 12 months.
"Population growth does equate to growing pains in traffic counts and efficiency," he said.
"People aren't just driving to work and driving home. They are making multiple traffic movements.
"One additional resident in the city usually equates to several additional vehicle trips in one day, so the effect of a small population increase can be exponential by multiplication factor on the traffic data.
"Whanganui has 12 sets of traffic lights. If you drive around town, you can work out where the growth is. It is manic at certain times around the Dublin St Bridge and near the City Bridge.
"The ongoing NZTA-managed flood reinstatement works along Anzac Pde adjacent to the Red Lion Tavern have been causing some disruption to traffic patterns, albeit with as efficient a traffic management plan as practical."
Council roading staff compared data for the 12 months to March 2019 for the Taupo Quay/Victoria Ave intersection. It's part of a prime route through the city where new and additional traffic signals were installed and the lane configuration changed in late 2018.
The data comes from traffic counts through the traffic lights programming sensors known as SCATS.
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The March traffic count showed a 20 per cent increase on Taupo Quay approaches through the traffic signals - 11 per cent eastbound and 9 per cent westbound.
There was a 13 per cent increase in traffic counts across the City Bridge and a 15 per cent increase in traffic counts northbound on Anzac Pde.
The council has been upgrading the city's SCATS because it can't get parts for the older technology.
"There has been a bedding in and tweaking process to react to changes in the system as well as ensuring coping mechanisms to the sudden spike in increased growth," Holmes said.
"With the new lights, there is the ability for Wellington Traffic Operation Centre (TOC) to log in and make amendments to the lights in real time as things are happening.
"We have a set plan in place from 4.45pm to 5.20pm at the St Hill St/Taupo Quay lights where it does what we tell it to try to clear traffic quickly. The SCATS system is manually overridden so traffic on Taupo Quay is pushed through a bit faster."
New pedestrian and cyclist crossing phases are contributing to delays for motorists at some intersections, Holmes said.
Current government policy gives priority to alternative modes of transport, particularly those that are carbon neutral, over motorists. It requires shared pathways to be given priority right of way in a SCATS programme.
"People have to change," Holmes said.
"Leave the car at home, park further away, use alternative transport."
Planning for future traffic movements
With the current infrastructure struggling to cope, Holmes says work is needed to plan for future traffic movements.
"We are intending to adopt a Network Operating Plan (NOP) as a framework to make robust decisions on our future infrastructure," he said.
NZ Transport Agency (NZTA) is contributing $100,000 which will enable the council to engage Abley transportation consultants, based in Auckland, to develop the Whanganui model.
"When we put in a funding application, NZTA wants hard evidence behind it and that costs money," Holmes said.
"The first port of call is to gather data to structure a business case to renew the Dublin St Bridge, based around our city growth."
The council's 10-year plan for 2018-2028 says a decision needs to be made within that timeframe on whether or not to renew the Dublin St Bridge and, if it is to be renewed, when. The estimated cost of replacing the bridge is $33.3M so NZTA subsidy would be essential.
"The Dublin St Bridge project is in the 10-year plan but NZTA doesn't see it as a high priority," Holmes said.
"NZTA has previously said we have two other bridges so why do we need a third one. This data will demonstrate that we need it.
"The model will dictate the size of the new bridge. The current bridge is deregistered to the point where we can't put heavy traffic on it. That means trucks are having to go a longer way round so they're incurring extra road user charges. They're not reducing their carbon emissions.
"The model will enable us to run scenarios and see what the bridge needs to do. We need to demonstrate the growth to central government. There are people moving in from Auckland and everywhere."
Holmes is gaining experience in the NOP process by working with Palmerston North City Council on implementing its plan and he will be involved with Manawatu District Council's plan, with Whanganui third cab off the rank.
"Logging traffic and freight routes into town are the biggest concerns to address through the model," Holmes said.
"Once we have the model, we can play with the data and decide where we want to direct traffic, logging movements etc then see what the cause and effect of that is.
"I hope to have the model in place before Christmas then we'll be tweaking it and making it work for us in the new year."
Have we got traffic problems?
Traffic seems to be getting many of us hot under the collar.
We asked our Facebook followers what they thought about Whanganui traffic and, if they thought it was a problem, where the issues were.
At last count we had more than 460 comments on our post, covering a range of issues but with some common themes.
There were those who said any suggestion of traffic issues in Whanganui was a joke and anyone who thought there was a problem should "build a bridge and get over it".
People from large cities in New Zealand and overseas said Whanganui road users had no idea what a traffic problem really was.
However, others said big city drivers were courteous, knew how to merge, let other traffic in and used their indicators - unlike many Whanganui drivers.
Even allowing for the fact that our post was accompanied by a photo of traffic on the Dublin St Bridge, that area came in for a high proportion of criticism about congestion, dangerous pedestrian crossings and poor use of the roundabouts.
Many people called for the bridge to be replaced, with some wanting a new four-lane bridge and one person suggesting a three-lane bridge with two lanes operating into the city in the mornings for peak traffic and changing to two away from the city in the evening.
Some thought another bridge should be built between Aramoho and Whanganui East to relieve congestion on the Dublin St Bridge and many weren't impressed by the new cycle bridge going in between Papaiti and Upokongaro, saying it should cater for motor vehicles as well.
The new road layout and traffic lights on Taupo Quay at the City Bridge and St Hill St copped a far bit of flak. Some people thought the St Hill St lights had created a problem where one did not previously exist.
Several respondents thought there should be dedicated right-turn signals for Grey St traffic at the London St-Grey St intersection and for Victoria Ave traffic at Victoria Ave-Glasgow St.
The timing of traffic signal sequences was an issue for many people who said some sequences were too short for more than a couple of vehicles to get through.
A number of people wanted traffic lights installed at the Victoria Ave-Liverpool St intersection.
Other criticisms were about the non- or incorrect use of indicators, particularly at roundabouts. On the other hand, some people wanted to ditch traffic lights and install roundabouts instead to keep traffic flowing.
Durie Hill residents said they were fed up with the roadworks between Portal St and the City Bridge but several praised motorists who allowed Durie Hill traffic to merge on to Anzac Parade.
Speeding on suburban streets and heavy traffic not bypassing the city were concerns for some.
The issue of parking was also raised, with some people saying the council needed to provide more public parking areas and making a plea for alternative parking meter payment methods for people who don't carry cash.